Process and apparatus for preparing webs from fibrous materials



Aug. 9, 1932.; E. F. SUNDSTROM ET AL 1,870,971 PROCESS AND APPARATUS FOR PREPARING WEBS FROM FIBROUS MATERIALS 3 Sheets- Sheet 1 Filed July 50, 1929 INVENTORSV El/mar fi'wzdsir' Karl E. Si/t ATTORNEYS Aug. 9, 1932- E. F. SUNDSTROM ET AL 1,870,971

PROCESS AND APPARATUS FOR PREPARING WEBS FROM FIBROUS MATERIALS Filed July so, 1929 3 Sheets-Sheet 2 luvs woes EINAR Su/vosrRzi/w KAZL, E. STEEN.

g- 9, 1932- E. F. SUNDS'iRGM 51' AL 1,870,971

PROCESS AND APPARATUS FOR PREPARING WEBS FROM FIBROUS MATERIALS Filed July 30. 1929 3 Sheets-Sheet 3 1 N VENTORS Eiiulr Sands Z1 ON/L li a. I'[ f) Ste em tSY ATTORNEYS I mama Au 9', 1 32 UNITED srA'r s "PATENT! OFFICE,

EINAB rnrrror sunnsrnou AND KARL EVALD swim, or sunnsvau, swmmn IPBOCES8 AND AP PABATUS FOR PREPARING WEBS FIBBOUS MATERIALS Application filed July 30, 1929, Serial No. 882,240, and in Sweden April 17, 1928.

This invention relates to a process and apparatus for absorption or extraction of l1qu1d from fibrous material, and more especially to .a process and apparatus for the production v from, or drying such a mixture of material bybeing subjected at one side to a higher 15 pressure than that at its other side when passing through a closed chamber, onto a drum of which a portion thereof is perforated in order to allow the removing of the liquid or moisture and drying air or gas,

' if such fluid is used, which on account of the higher pressure ispressed through and out of the mixture of material.

- In the handling of a mixture of material, either of two ,diflerent ways may be used.

25 By one way, the mixture. fills entirely the closed chamber, which is subjected to a high pressure either by pumping the mixture of material directly under high pressure lnto the chamber, or by introducing the mixture of material into the closed chamber from a hopper situated at a suitably adapted height, the other side of the mixture or path. of material at the same timebeing freely exposed to the free air.

By the other way, the mixture of material only partly fills theclosed chamber, which in this case is-subjected to a higher pres sure by means ofa pressure fluid, consisting of cold, or heated air, or gas or a gas mixture, which is introduced into the closed chamber by means of a steam injector, compressor or similar device, and with the high pressure adapted toth'e conditions, so that the pressure fluid on account of this high pressure penetrates between, or'makes its way past,"

the fibres in such a mixture 'of material into i With a continuous path of material or a mixture of material of a solid consistence,

only the last mentioned way with a pressure fluid can be used.

Apparatus of various construction for taking-up, removing the water from, and drying materials depositedin a'liquid,'such as paper, cellulose, wood-pulp and the like, are

old "and Well known, and these might be said to be divided into two main sect ons, a wet section and a dry section, which sections, sep-.

arately, may be constructed in diflferent ways. a

The wet section may, for instance, be'constructed with plane-endless wire-cloth com bined with felt-presses or corrugated rotatable high-pressure presses, or rotating suction sieves constructed with similar felt-presses or corrugated presses, or any other taking-up member, where the removing of water takes place by means of mechanical pressing, or vacuum, or both of them, while the drying section may, for instance, be constructed with variable sized cylinders heated by steam about which the path of material is carried during the rotation of the cylinders, and the gradual drying of the material effected by heat in the transmission of steam through the cylinders in the path of the material.

The treatment of material in the above described wet section, especially if corru gated, feltless presses are used, 1s-of such a nature that, if the fibres of the material are not directly damaged, the path of material is so hard pressed together, that the work for the disintegration of the path of material necessary at the paper mills rendered more diflicult and mademore expensive. In addi tion .it is a fact,that the fibres in the la ers of the path of material lying farthest o are damaged through the relatively high temperaure in the steam cylinders.

Heretofore attempts have been made to avoid this last-mentioned disadvantage by,

a constructon of dry ng section, at which the i path of material is'dried by direct contact with warm air, which thusobtains an opportunity of sweeping either over a continuously f fed path of material,"or.,over the material to be dried, the latter having first in a special way been comminuted in flakes. or fibres,"

which are intimately mixed with the drying air by agitators constructed for this purpose.

Even if the fibres by this method of drying avoid being damaged, there remains, however, the already mentioned disadvantage from the wet section, namely, that the WOIkprocess, described above.

In the accompanying drawings:

Figure 1 is a vertical sectional elevation of one form of apparatus for carrying out the process in accordance with the invention.

Figure 2 is a similar view of another form of apparatus.

Figure 3 is a similarview of another form of apparatus.

Figure 4 is a similar view of another form of apparatus.

Figures 5, 6, and 7 are vertical sec ional elevations of still further forms of construction of apparatuses.

Referring to the drawings, particularly Fig. 1 there is shown a pressure box or receptacle 1, the bottom of which is arranged a perforated, rotatable drum 2 provided either with or without special filtering-cloth about ,7

its mantle. The mixture of material is introduced into the pressure box 1 through the pipe 3 from a hopper 4 located at a suitable elevation, the pressure 2 box being thus always filled with a mixture of material under a'pressure higher than the pressure at the inside of the drum; A layer forming a path of material 5 is formed on the upper side of the rotating drum 2 at some point of its circumference, where necessary packing is arranged, this being effected in anywell known manner, so that the path of material is brought to pass between the rotating drum 2 and a r0- tating taking-01f cylinder 6. The packing of the latter against the wall of the pressure box is also efi'ected in any desirable manner, for instance by an elastic element 7, which on account of the pressure in the box is pressed against the cylinder 6 and tightens against the same.

Packing between the front sides of the pressure box, on the one hand, and between the rotatable drum 2 and the taking-oi? cylinder, on the other hand, is also carried out in the usual well known manner. The drying of the contents 'or'the path of material may be regulated atwill within certain limits by raising or lowering the pressure. in the pressure box, or by regulating the concentration ofthe introduced mixture of material, or by both expedients.

The liquid pressed out of the material is- 1 drum 2. The-path of material 5 is taken off from thecylinder .6, and the pat-kings are effected'by an elastic element 7, identically as in Fig. 1.

The mixture of material is pressed in through the pipe 3 by means of a force-pump or an elevated hopper 4. At the same time a pressure fluid, for instance air,- of a high or low temperature, or gas or a gas mixture is pressed in through the pipe 8. The level a of the mixture of material in the pressure box 1 is determined by regulation of the supply through the two plp'es 3 and 8. The layer of material which constantly is formed on the level a of the mixture of' material, and the removing of water and the drying respectively is effected thereby,.that the pressure fluid, on account of the higher pressure in the The path of material finally leaves the drum- 2in any desirable manner. By proportioning the size of the apparatus and regulating the rotation of the drum, the concentration of the mixture of material, andthe temperature, and the pressure and temperature of the pressure fluid, any desired dryness of substance contents of the material to be treated is reached.

With certain qualities of mixtures of material more difficult to be treated, it has appeared to be advantageous to precisionize the passage ofthe pressure fluid through the drum 2 follows the rotating drum above the mixture or path of material with the aid of an endless felt or wire-clothlO placed on rolls 9 in the pressure box 1, which wire-cloth bymeans of adriving device on any of the rolls, in a known way, obtains a suitable peripheral speed in proportion to the outer circumference of the path of material.

For economical reasons, it has appeared to be advantageous to apportion the removingof-the-water and drying, in certain cases, to

two or more pressure boxes, each of the same construction and mode of operation as hereto foredescribed. The only difl'erence is, that the path of material 5, in such. acase, isintroduced into th pressure box with the aid of a roll 11 as shown in Fig.3. 4

The embodiment according to Fig. 4 involves two or morerotatable drums 2, these being surrounded by a common .mantle, which forms the closed chamber. This chamber is separated into different compartments by means of dividing walls 12, to enable the introduction of pressure fluid with varying pressures and varying temperatures respectively into these different compartments.

,If desired, the high pressure in the pressure box may also be regulated relatively to the pressure at the other side of the mixture or path of material by combining'the rotatable drum of some, or of all of the described embodiments with another pressure box arranged in such a way, that the lower side of the mixture or path of material is subjected to a pressure not coming up to, or exceeding the atmospheric pressure, but which,"under all circumstances, is lower than the pressure at the upper side of the mixture of material.

Even other embodiments are possible, where the closed chamber is obtained in a way as shown for instance in Figs. 5, 6 and 7.

Further, the invention may of course in those cases, where suitable, be combined with rotating presses with or without felt, or for instance with drying sections used to increase the dry substance contents, or the temperature, or both these things, or the path of material by pressing and heating respectively.

This invention may, of course, with regard to the process as well as to the apparatus, easily be so applied, that a continuous path effected by the treatment in the closed chamber leaves said chamber either in the form, of a continuously running path, or in the form of an intermittently fed path (the path is in both cases continuous) thereby, that the rotating drum in Figs. 1 2 and 3 of the drawings or corresponding parts of other embodiments, are arranged for continuous or intermittent rotation.

Having now described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In an, apparatus for separating fibrous material from a liquid holding the material in suspension, the combinationof a pressure chamber; a rotatable perforated drum forming a depositing bed in the pressure chamber for the material; and means for introducing said suspension into the chamber and for feeding it in contact with the bed under a substantial static head above atmospheric pressure, thereby producing a continuous compact path of material on the drum. 9 2. In an apparatus for separating fibrous material from a liquid holding the material in suspension, the combination of a pressure chamber; a rotatable perforated drum form- \ing a depositin bed in the pressure chamber for the material; means for introducing said suspension into the chamber and for feeding it in contactwith the bed under a substantial static head above atmospheric pressure, there-.

by producin a continuous compact path of material on t e drum; and means for supplying gaseous fluid under such pressure' -to the pressure chamber that apart of the drum surface is abovethe liquid level in the chamber.

3. In an apparatusfor separating fibrous material from a liquid holding it in suspension, the combination of a pressure box; a

the box and for feeding it in contact with the bed under a substantial static head above atmospheric pressure, thereby producing a continuous compact path of material; means for supplying gaseous fluid under such pressure to ,the'box 'thata part of the drum surface is above the liquid level in the box; an endless perforated band in the pressure box, contacting with the material onthe bed in the gaseous fluid space; and means for driving said band.

4.- In an apparatus for separating fibrous material from a liquid holding it in suspension, thecombination of a pressurebox; a rotatable perforated drum forming a depositing bed inthe pressure box for the material; means for introducing said suspension into the box and for'feeding it in contact with the bed under a substantialstatichead above atmospheric pressure, thereby producing a continuous compact path of material;

means for supplying gaseous fluid under suchpressure to the box that a part of the drum surface is above the liquid level in the box; an endless perforated band in the pressure box, contacting with the material on the bed in the gaseous fluidspace; means for driving said b and; and a take-off cylinder for the layer of material on the bed, said'cylinder being mounted in the opening in the box' wall through which the path'of material is taken from the drum, and being tightened against said box wall by means of packing elements.

5. The herein-described process. consistin 1n separating fibrous material from liqui holding 1t in suspension by introducing the suspension into a pressure chamber, and feeding it in contact with a permeable bed in said chamber under a substantial static head above the atmospheric pressure.

6. The herein-described process in which the fibrous material, separated from the liquid. which has held it in suspension, forms a layer on a rotatable perforated drum and is subjected to the action of a gaseous fluid under a pressure above the atmospheric pres,- sure for removing water from the layer.

7. In an apparatus for separating fi rous material from a liquid holdingthe ma erial in suspension, the combination of a pressurechamber; a rotatable'perforated drum forming a depositin bed in the pressure chamber for the materia means for introducing said suspension into the chamber and for feeding it in contact with the bed under a substantial static head above. atmospheric pressure, thereby producing a continuous compact path of material on the drum; a separate closed chamber, the bottom of which comprises part of the surface of a rotating perforated drum; means such as feedand takeoff cylinders for feeding into and out of this second chamber the layer of material already consolidated in the first chamber; and means for supplying gaseous fluid under pressure to the second chamber.

8. In an apparatus for separating fibrous material from a liquid holding the material in suspension, the combination of a pressure chamber; a rotatable perforated drum forming a depositing bed In the pressure chamber for the material, means forintroduclng said suspension into the chamber and for feeding it in contact with the bed under a substantial static head above atmospheric pressure,

thereby producing a continuous compact path of material on thedrum; a separate closed chamber; means such as feedand take-ofi' cylinders for feeding into and out of this second chamber the layer of material already consolidated in the first chamber;

and means for supplying gaseous fluid under pressure to the second chamber, the bottom of the second chamber comprising a part of i the surface of a v plurality of rotatable perforated drums. I

9. In an apparatus for separating fibrous material from a liquid holding the material in suspension, thecombination of a pressure chamber; a rotatable perforated drum forming a depositing bed in the pressure chamber for the material; means for introducing said suspension into the chamber and for feeding it in contact with the bed under a substantial static head above atmospheric pressure, thereby producing a continuous compact path of,-matcrial on the drum; a separate closed chamber; means such as feedand take-ofi' cylinders for feeding into and out of this second chamber the layer of material already consolidated in the first chamber;

and means for supplying gaseous fluid under pressure to the second chamber, said second chamber being subdivided into two or more compartmen s by dividing Walls.

10. In an apparatus for separating fibrous material from a liquid holding the material insuspension, the combination of a pressure chamber; a rotatable perforated drum forming a depositing bed in thepressure chamber for the material; meansfor introducing said a suspension into the chamber and for-feeding 1t 1n contact wlth the bedunder a substantial static head'above atmospheric pressure,

thereby producing a continuous compact path of material on the drum; and means for "arylngthe ressure inside the drum so as to adjust t e difference of pressure through the layer of material.

In witness whereof, we have hereunto signed our names.

EINAR FRITIOF sUNDsTRoM. KARL EVALD sTnEN. 

